Relationship between XRCC1 Polymorphism and Acute Complication of Chemoradiation Therapy in the Patients with Colorectal Cancer / 대한방사선종양학회지

ABSTRACT

PURPOSE: It is well known from clinical experience that acute complications of chemoradiation therapy vary from patients to patients. However, there are no known factors to predict these acute complications before treatment starts. The human XRCC1 gene is known as a DNA base excision repair gene. We investigated the possibilities of XRCC1 gene polymorphisms as a predictor for the acute complications of chemoradiation therapy in colorectal cancer patients. MATERIALS AND METHODS: From July 1997 to June 2003, 86 colorectal cancer patients (71 rectal cancer, 13 sigmoid colon cancer and 2 colon cancer patients) were treated with chemoradiation therapy at the Department of Radiation Oncology, Inha University Hospital. Twenty-two patients were in stage B, 50 were in stage C, 8 were in stage D and 6 patients were unresectable cases. External radiation therapy was delivered with 10MV X-ray at a 1.8 Gy fraction per day for a total dose of radiation of 30.6~59.4 Gy (median 54 Gy). All the patients received 5-FU based chemotherapy regimen. We analyzed the acute complications of upper and lower gastrointestinal tract based on the RTOG complication scale. The initial and lowest WBC and platelet count were recorded during both the RT period and the whole treatment period. Allelic variants of the XRCC1 gene at codons 194, 280 and 399 were analyzed in the lymphocyte DNA by performing PCR-RFLP. Statistical analyses were carried out with the SAS (version 6.12) statistical package. RESULTS: When all the variables were assessed on the multivariate analysis, recurrent disease revealed the factors that significantly correlated with upper gastrointestinal acute complications. Arg399Gln polymorphisms of the XRCC1 gene, the radiation dose and the frequencies of chemotherapy during radiation therapy were significantly correlated with lower gastrointestinal complications. Arg399Gln polymorphisms also affected the decrease of the WBC and platelet count during radiation therapy. CONCLUSION: Although the present sample size was too small for fully evaluating this hypothesis, this study suggests that Arg399Gln polymorphisms of the XRCC1 genes may be used as one of the predictors for acute complications of chemoradiation therapy in colorectal cancer patients.